1. Field of the Invention
The present invention relates to a so-called outdoor portable gas cooking stove, and more particularly, to a burner structure of a portable gas cooking stove.
2. Description of the Related Art
FIG. 1 shows an example of a portable gas cooking stove known in the art.
Normally, the portable gas cooking stove 10 includes a gas cartridge 11 filled with compressed combustible gas, and a gas burner 12 mounted detachably on the gas cartridge 11. The gas cartridge 11 and the gas burner 12 are coupled to each other in a hermetically sealed condition through a gasket 13.
The gas burner 12 is comprised of a plug fitting 14 which is connected to the gas cartridge 11 and through which combustible gas supplied from the gas cartridge 11 passes, a gas flow adjusting spindle 15 which adjusts a degree of opening of a gas passage formed inside the plug fitting 14 to thereby adjust a flow of the combustible gas passing through the plug fitting 14, a burner head 16 with a number of openings 16a and a flame hole 16b greater in area than the openings 16a, both formed on a surface thereof, a mixing tube 17 connecting the plug fitting 14 to the burner head 16, a plurality of kettle holders 18 that are fixed on the mixing tube 17 and extend over the burner head 16, and an igniter 19 mounted on a support 19a.
The flame hole 16b is covered with a mesh net.
The portable gas cooking stove 10 having the above-mentioned structure is used as follows.
The combustible gas is filled in the gas cartridge 11 in a pressurized condition. Hence, when the gas passage is made open through the gas flow adjusting spindle 15, the combustible gas in a pressurized condition enters the mixing tube 17 from the gas cartridge 11 through the plug fitting 14. Thus, the combustible gas enters the mixing tube 17 with a gas flow thereof being adjusted by the gas flow adjusting spindle 15.
The mixing tube 17 is formed with a number of openings 17a (only one of them is illustrated in FIG. 1). External air is absorbed into the mixing tube 17 through the openings 17a by virtue of negative pressure produced when the combustible gas passes through the mixing tube 17. The combustible gas is mixed with air entering the mixing tube 17 through the openings 17a, into a gas mixture of the combustible gas and air.
After entering the burner head 16, the gas mixture is discharged through both the openings 16a and the flame hole 16b. The mixture gas having been discharged from the flame hole 16b is ignited by the electric igniter 19 located in the vicinity of the burner head 16, and the mixture gas having been discharged through the openings 16a is also ignited by virtue of ignition of the mixture gas discharged through the flame hole 16b.
Flame of burning gas mixture heats an object to be heated such as a pan, kettle, food, etc., put on the kettle holders 18.
The flame hole 16b is formed generally by the steps of forming a hole at a surface of the burner head 16, and covering the hole with a mesh net at an inner wall of the burner head 16.
However, since the burner head 16 is generally small in size, it is a laborious step to cover a hole formed at a surface of the burner head 16, with a mesh net at an inner wall of the burner head 16. Accordingly, the step of fabricating the burner head 16 takes much time and much labor.